Abstract
We report the discovery of a hot Jupiter on a 3.28-day orbit around a 1.08 Ma G0 star that is the secondary component in a loose binary system. Based on follow-up radial velocity observations of TOI-858 B with CORALIE on the Swiss 1.2 m telescope and CHIRON on the 1.5 m telescope at the Cerro Tololo Inter-American Observatory (CTIO), we measured the planet mass to be 1.10a0.07+0.08 MJ. Two transits were further observed with CORALIE to determine the alignment of TOI-858 B b with respect to its host star. Analysis of the Rossiter-McLaughlin signal from the planet shows that the sky-projected obliquity is λ = 99.3a3.7+3.8 . Numerical simulations show that the neighbour star TOI-858 A is too distant to have trapped the planet in a Kozai- Lidov resonance, suggesting a different dynamical evolution or a primordial origin to explain this misalignment. The 1.15 Ma primary F9 star of the system (TYC 8501-01597-1, at ρ ~11) was also observed with CORALIE in order to provide upper limits for the presence of aplanetary companion orbiting that star.
Original language | English (US) |
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Article number | A70 |
Journal | Astronomy and Astrophysics |
Volume | 679 |
DOIs | |
State | Published - Nov 1 2023 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- Binaries: visual
- Planets and satellites: detection
- Planets and satellites: dynamical evolution and stability
- Planets and satellites: individual: TOI-858A
- Planets and satellites: individual: TOI-858B